[LiveComponent] `in-view` and `tab-active` modifiers for polling

From https://github.com/symfony/ux/issues/102:

> Future D) Polling enhancements: (1) poll less often when the browser tab is not active and (2) don't start polling until visible

```twig
<div
    {{ attributes }}
    data-poll="delay(500)|in-view|tab-active|$render" {# only poll when component is in viewport and browser tab is active #}
>
```